[Insight-users] Re: Speed of B-Splines Deformable Registration

[Andy Eow]

Hi Luis,

I am running my data on DeformableRegistration6.cxx. The low resolution step 
takes abt 24 hrs, whilst the high resolution step is still in its first 
iteration after 48 hrs. I just wanted to check if this is normal or is there 
certain pre-processing necessary?

Thanks.

Cheers,
Andy


----- Original Message ----- 
From: "Luis Ibanez" <luis.ibanez at kitware.com>
To: "Andy Eow" <vtkitk at hotmail.com>
Cc: <insight-users at itk.org>
Sent: Friday, October 08, 2004 2:01 PM
Subject: Re: Speed of B-Splines Deformable Registration


>
> Hi Andy,
>
> The current implementation of BSpline registration
> is not quite optimal.
>
> There are a number of standard practices that we
> are not taking advantage of in the current ITK
> implementation.
>
> For example, the computation of Metric Derivatives
> could be done by considering only the area of influence
> of a particular BSpline grid node, instead of computing
> it over the entire image.
>
> The group of Daniel Rueckert group at the Imperial College
> of London is currently porting some of their optimized
> BSpline registration to ITK classes, however, it may take
> a while before they are fully integrated in the toolkit.
>
> In the meantime, your best options are:
>
>   1) Do multi-Resolution on the Image Data
>
>   2) Do multi-Resolution on the BSpline grid
>      (see example DeformableRegistration6.cxx)
>
>
> Please let us know if you have further questions.
>
>
>   Thanks
>
>
>      Luis
>
>
>
> ----------------------
> Andy Eow wrote:
>
>> Hi,
>>  I'm trying to run the DeformableRegistration4.cxx example which uses 
>> B-Splines for non-rigid registration. My goal is to eventually replace 
>> the means squares metric in this example with a MI metric. However before 
>> that, I'm just simply running a slightly modified version of the example 
>> first to take in a 3D volume (200x200x200) instead of a 2D slice. After 
>> running for 2+ hours, this is all I get:
>>  F = 21.4132, GNORM = 1.62984
>> *************************************************
>>    I   NFN    FUNC        GNORM       STEPLENGTH
>>    1    2        18.592       1.131       0.614
>>    2    3        16.318       0.835       1.500
>> With a maximum iteration number at 1000, this process is going to take 
>> quite a few days to complete. I'm running this on a Pentium 1.6M with 1GB 
>> RAM. Just wanted to do a sanity check to see if this sounds normal. If 
>> not, what kind of worst case running times should I be expecting on a 3D 
>> volume of size 200x200x200?
>>  Cheers,
>> Andy
>>
>
>
>
>
>